The individual section or IS glassware forming machine is well known and includes a plurality of sections each having mechanisms for forming articles of glassware in a time sequence of predetermined steps. The forming mechanisms in each section are typically operated by pneumatic motors or actuators. The pneumatic motors are controlled by a valve block which in turn is controlled by an electronic control system having a computer for each individual section such as, for example, the system disclosed in U.S. Pat. No. 4,152,143, granted to W. T. Dowling and D. S. Farkas and assigned to the assignee of the present invention. Individual sections may include a plurality of position sensors coupled to the forming mechanisms to monitor their position as disclosed in U.S. Pat. No. 4,338,116, granted to N. T. Huff et al. The output signals from the sensors are provided to a corresponding individual section computer which processes the output signals.
The position sensors can be inductive proximity sensors, in which case the coupling between the forming mechanism and the position sensor is an electrical conductor mounted on the mechanism. The electrical conductor serves as a target for the magnetic field generated by the sensor. A significant difficulty encountered in using inductive proximity sensors to sense the position of the mechanism is that the target must be positioned more or less accurately in front of the sensor. The accuracy required is determined by the switching range of the sensor/target configuration, i.e., the minimum transfer distance that the target or sensor must move to cause the output of the sensor to change its state. A large switching range is desired in order to make the positioning of the target in front of the sensor noncritical. When using the conventional square-faced target, the switching range of the sensor, i.e., the physical "window" in which the target can be placed, is too small.